Genetic Engineering
Genetic Engineering Genetic Engineering: The development and application procedures, and technologies that allow you to directly manipulate an organisms DNA We can manipulate DNA and genes to alter organisms or make them produce a product we need.
Genetic Engineering (g.e) 1. It is the process of inserting genes of interest into specific organisms for either a medical or scientific benefit. 2. Gene therapy is the process of inserting a missing gene into an organism. 3. Bacteria are often used as the factories to produce a protein from a cloned gene. This has led to the production of human insulin,gh & erythropoietin..etc. 4. The gene must be cloned into an expression vector, usually a plasmid with special features that allows it to be transcribed & translated in a host cell.
Genetic Engineering in Agriculture 1. Disease resistance e.g. corn & cotton 2. Nitrogen fixation 3. Frost-free plants e.g. strawberries & potatoes 4. Tomatoes with a long shelf life deactivating the gene in tomato which produce ethylene. 5. Increased milk production giving cows bovine somatotropin (BST) growth hormone. 6. Good predator attraction strawberry gene on mustard plants produces a chemical attractant for predator mites that eat the herbivorous spider mites.
Transgenic tomato plant : Recombinant DNA methods have produced plants that resist defoliation by caterpillars, with longer shelf life. Fig. 13-18, p.349
Genetic engineering: Changing the DNA in living organisms to create something new. This organisms are called Genetically Modified Organism (GMO) Example: Bacteria that produce human insulin Genetically Modified organism are called transgenic organism; since genes are transferred from one organism to another.
Some genetic engineering techniques are as follows: 1. Artificial selection 2. Cloning 3. Gene splicing 4. Gel electrophoresis: analyzing DNA
1. Artificial selection: breeders choose which organism to mate to produce offspring with desired traits. They cannot control what genes are passed. When they get offspring with the desired traits, maintain them. Three types of artificial selection: A. Selective breeding B. Hybridization C. Inbreeding
A. Selective breeding: when animals with desired characteristics are mated to produce offspring with those desired traits. Passing of important genes to next generation. Example: Champion race horses, cows with tender meat, large juicy oranges on a tree.
Examples of selective breeding: Angus cows are bred to increase muscle mass so that we get more meat, Egg-Laying Henproduces more eggs than the average hen
Selective breeding occurs when you choose the best male and female to breed. This allows you to fine tune and control the traits The offspring or babies will then have the best traits. Then you continue to breed those organism with the best traits, those traits will be maintained.
Selective Breeding Selective Breeding: allowing only those organisms with desired characteristics to reproduce. How could you use selective breeding to develop dogs with more intelligence? Selective breeding takes advantage of natural genetic variation (the trait must already exist in the population)
Selective Breeding 2 Methods of selective breeding 1. Hybridization: crossing dissimilar individuals together to get the best of both organisms Ex: Killer Bees While attempting to create a bee that produces more honey in tropical climates scientist bred a European honey bee with a African honey bee. 2. Inbreeding: the continued breeding of individuals with similar characteristic Ex: Purebred Dog Breeds dog breeds are created by breeding individuals with similar characteristics to ensure that the combination of traits will be passed on to the next generation.
B. Hybridizations: two individuals with unlike characteristics are crossed to produce the best in both organisms. Example: Luther Burbank created a disease resistant potato called the Burbank potato. He crossed a disease resistant plant with one that had a large food producing capacity. Result: disease resistant plant that makes a lot of potatoes.
Other Examples of hybridization: 1. Liger: lion and tiger mix
2. Grape + apple= grapple. The fruit tastes like grapes and looks like apple.
C. Inbreeding breeding of organism that genetically similar to maintain desired traits. Dogs breeds are kept pure this way. Its how a Doberman remains a Doberman. It keeps each breed unique from others. Risk: since both have the same genes, the chance that a baby will get a recessive genetic disorder is high. Risks: blindness, joint deformities.
In order for selective breeding to work, you need a wide variation of genetic traits. Selective Breeding Explain you cannot use selective breeding to create a monkey that glows in the dark? How do new traits get introduced into a population? Induce mutations to develop new traits in a population (Mutations are the ultimate source of genetic traits)
Selective Breeding Limitations of selective breeding and mutations: Selective breeding requires traits already exists in a population we can not make new traits. Mutations are unpredictable and will not create the exact traits that we want. (most mutations are harmful to the organism)
Variation: difference between individuals of a species. The differences are in the genes but we see the physical differences. For example: Some humans have blond hair and some have brown. This is a variation among humans. Inbreeding decreases variations.
2. Cloning: creating an organism that is an exact genetic copy of another. There are human clones in our school. Identical twins are naturally created clones.
Eggs are haploid Haploid: half the chromosomes, 23 in humans Body cells are diploid: Diploid: two sets of chromosomes, one from mother and one set from father 46 in humans.
This picture represents gene splicing. However, DNA is much smaller. Its done with high tech lab equipment since DNA, is too small to hold or see without a microscope. The red piece the woman is holding is an insulin gene from a human being. It is being combined with DNA from a bacteria. Creates recombinant DNA, something that has never existed before.
Benefits: Insulin is cheaper There are no side effects because it is human insulin. We once used pig insulin but there are side effects and it is more expensive.
How is gene splicing done? 1. A restriction enzyme cuts the insulin gene out of the human DNA. 2. A plasmid is removed from a bacteria and cut with a restriction enzyme
3. The human gene is place into the bacteria plasmid 4. The plasmid is placed back into the bacteria. The cell now has directions (DNA) to make insulin. That's exactly what it does. Its human insulin, bacteria do not make insulin on their own. Plasmid with insulin gene
This is called transformation: when a gene from one organism is transferred to different organism. The organisms that have DNA transferred to them are called transgenic organisms. trans: means different, genic: refers to genes Genetic engineering has given rise to a new technological field called biotechnology (technology of life).
1. Transgenic (GMO) animals: genes inserted into animals so they produce what humans need. Why?: A way to improve the food supply: A. Transgenic cows: gene inserted to increase milk production.
B. Spider goat: gene from spider inserted into goat. Goats makes silk of the spider web in their milk. Flexible, stronger than steel. Used in bullet proof jackets.
C. Glow-in-the-dark cats Scientist used a virus to insert DNA from jellyfish The gene made the cat produce a fluorescent protein in its fur.
2. Transgenic bacteria: gene inserted into bacteria so they produce things humans need. For example: insulin and clotting factors in blood are now made by bacteria.
3. Transgenic plants: plants are given genes so they meet human needs. A. Transgenic corn: given a gene so corn produces a natural pesticide. Now they don t have to be sprayed with cancer causing pesticides. 25% of all corn is like this.
B. Venomous cabbage Gene from a scorpion tails inserted into cabbage. Cabbage now produces that chemical. Why? Limit pesticide use while still preventing insects from damaging crops. Corporations state the toxin is modified so it isn t harmful to humans.
C. Banana vaccines Virus is injected into a banana, the virus DNA becomes part of the plant. As the plant grows, it produces the virus proteins but not the disease part of the virus. When people eat a bite, their immune systems creates antibodies to fight the disease just like a traditional vaccine Vaccines for hepatitis and cholera
Medicinal eggs British scientists have created a breed of genetically modified hens that produce cancer-fighting medicines in their eggs. The animals have had human genes added to their DNA so that human proteins are secreted into the whites of their eggs, along with complex medicinal proteins similar to drugs used to treat skin cancer and other diseases. What exactly do these disease-fighting eggscontain? The hens lay eggs that have mir24, a molecule with potential for treating malignant melanoma and arthritis, and human interferon b-1a, an antiviral drug that resembles modern treatments for multiple sclerosis.
Fast-growing salmon genetically modified salmon grows twice as fast as the conventional variety the photo shows two same-age salmon with the genetically altered one in the rear.
A virus is often used to deliver DNA. In the movie I Am Legend, A healthy gene was inserted into a virus. The virus invaded the cancer cells and inserts the healthy gene to cure cancer. Worked at first but the virus mutated and became deadly. This is being attempted in real life.
Gene therapy: when disease causing genes are cut out and good gene are inserted. Restriction enzymes are used to cut out bad genes. Viruses are used to insert good genes. Not approved for human use yet. Some possible side effects.
4. Gel electrophoresis: a technique used to compare DNA from two or more organisms. Why compare DNA: 1. Find your baby s daddy 2. Who committed a crime. 3. How closely species are related.
How is electrophoresis done? A. The DNA is cut into fragments with a restriction enzyme. B. The cut DNA is then put into the wells of a machine filled with gel. The gel is spongy and the DNA squeezes through the pores.
C. The machine is plugged in and the fragments get separated based on their size. The smaller fragments move further than the large.
Separation of DNA based on size of fragments. Electrophoresis results Final result of electrophoresis
Electricity provides the energy Why does DNA move? DNA has a negative charge. When the machine is plugged it, its moves towards the positive pole created by the electricity
electrophoresis
Your DNA is so unique its considered to be a DNA fingerprint. Gel electrophoresis will separate your DNA differently from anyone else. Nova: who done it http://www.pbs.org/wgbh/nova/sheppard/analyze.html http://www.teachersdomain.org/asset/tdc02_i nt_creatednafp2/